2 * Copyright (c) 1990 University of Utah.
3 * Copyright (c) 1991, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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38 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93
42 #include <sys/param.h>
43 #include <sys/systm.h>
47 #include <sys/mutex.h>
52 #include <vm/vm_object.h>
53 #include <vm/vm_page.h>
54 #include <vm/vm_pager.h>
55 #include <vm/vm_zone.h>
57 static void dev_pager_init __P((void));
58 static vm_object_t dev_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t,
60 static void dev_pager_dealloc __P((vm_object_t));
61 static int dev_pager_getpages __P((vm_object_t, vm_page_t *, int, int));
62 static void dev_pager_putpages __P((vm_object_t, vm_page_t *, int,
64 static boolean_t dev_pager_haspage __P((vm_object_t, vm_pindex_t, int *,
67 /* list of device pager objects */
68 static struct pagerlst dev_pager_object_list;
69 /* protect against object creation */
70 static struct sx dev_pager_sx;
71 /* protect list manipulation */
72 static struct mtx dev_pager_mtx;
75 static vm_zone_t fakepg_zone;
77 static struct vm_zone fakepg_zone_store;
80 static vm_page_t dev_pager_getfake __P((vm_offset_t));
81 static void dev_pager_putfake __P((vm_page_t));
83 struct pagerops devicepagerops = {
96 TAILQ_INIT(&dev_pager_object_list);
97 sx_init(&dev_pager_sx, "dev_pager create");
98 mtx_init(&dev_pager_mtx, "dev_pager list", MTX_DEF);
100 fakepg_zone = &fakepg_zone_store;
101 zinitna(fakepg_zone, NULL, "DP fakepg", sizeof(struct vm_page), 0, 0, 2);
103 fakepg_zone = zinit("DP fakepg", sizeof(struct vm_page), 0, 0, 0);
107 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff)
115 mtx_assert(&Giant, MA_OWNED);
117 * Make sure this device can be mapped.
120 mapfunc = devsw(dev)->d_mmap;
121 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) {
122 printf("obsolete map function %p\n", (void *)mapfunc);
127 * Offset should be page aligned.
129 if (foff & PAGE_MASK)
132 size = round_page(size);
135 * Check that the specified range of the device allows the desired
138 * XXX assumes VM_PROT_* == PROT_*
140 npages = OFF_TO_IDX(size);
141 for (off = foff; npages--; off += PAGE_SIZE)
142 if ((*mapfunc) (dev, off, (int) prot) == -1)
146 * Lock to prevent object creation race condition.
148 sx_xlock(&dev_pager_sx);
151 * Look up pager, creating as necessary.
153 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
154 if (object == NULL) {
156 * Allocate object and associate it with the pager.
158 object = vm_object_allocate(OBJT_DEVICE,
159 OFF_TO_IDX(foff + size));
160 object->handle = handle;
161 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
162 mtx_lock(&dev_pager_mtx);
163 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list);
164 mtx_unlock(&dev_pager_mtx);
167 * Gain a reference to the object.
169 vm_object_reference(object);
170 if (OFF_TO_IDX(foff + size) > object->size)
171 object->size = OFF_TO_IDX(foff + size);
174 sx_xunlock(&dev_pager_sx);
180 dev_pager_dealloc(object)
185 mtx_lock(&dev_pager_mtx);
186 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
187 mtx_unlock(&dev_pager_mtx);
189 * Free up our fake pages.
191 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
192 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
193 dev_pager_putfake(m);
198 dev_pager_getpages(object, m, count, reqpage)
212 mtx_assert(&Giant, MA_OWNED);
213 dev = object->handle;
214 offset = m[reqpage]->pindex;
215 prot = PROT_READ; /* XXX should pass in? */
216 mapfunc = devsw(dev)->d_mmap;
218 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop)
219 panic("dev_pager_getpage: no map function");
221 paddr = pmap_phys_address((*mapfunc) (dev, (vm_offset_t) offset << PAGE_SHIFT, prot));
222 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
224 * Replace the passed in reqpage page with our own fake page and free up the
225 * all of the original pages.
227 page = dev_pager_getfake(paddr);
228 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
229 for (i = 0; i < count; i++) {
232 vm_page_insert(page, object, offset);
234 return (VM_PAGER_OK);
238 dev_pager_putpages(object, m, count, sync, rtvals)
245 panic("dev_pager_putpage called");
249 dev_pager_haspage(object, pindex, before, after)
263 dev_pager_getfake(paddr)
268 m = zalloc(fakepg_zone);
270 m->flags = PG_BUSY | PG_FICTITIOUS;
271 m->valid = VM_PAGE_BITS_ALL;
279 m->phys_addr = paddr;
288 if (!(m->flags & PG_FICTITIOUS))
289 panic("dev_pager_putfake: bad page");
290 zfree(fakepg_zone, m);